I honestly think persuasion as a stat should be removed. The option to play peacefully and sweet-talk or fail / murder everyone should be there by default. Also a side annoyance with persuasion is when NPCs run up to you and talk to the person in your party closest to them, rather than the one I leveled persuasion on. It's annoying!
Imo, they should bake Barter into Persuasion, and then bake Sneak into Thievery as sneak is p. damn useless on it's own. It would make sense that if you're good at talking you'd also be good at trade, and if you're looking to be a thief you'd also be naturally stealthy.